Controllable pitch propeller



Feb. 1, 1966 E. L. LORENZ GON'IROLLABLE PITCH PROPELLER Filed July 9, 1964 2 Sheets-Sheet l INVENTOR. 500/1/ 4. mam/z Feb. 1, 1966 E. LORENZ 3,232,350

CONTROLLABLE PITCH PROPELLER Filed July 9, 1964 2 Sheets-Sheet 2 INVENTOR. ADO/V A. ZJFfA/Z ,4 TraP/U V5 United States Patent 3,232,350 CONTROLLABLE PITCH PROPELLER Eldon L. Lorenz, Grand Rapids, Mich., assignor to Michigan Wheel Company, Grand Rapids, Mich., a corporation of Michigan Filed July 9, 1964, Ser. No. 381,326

3 Claims. (Cl. 170-16032) This invention relates to a marine propeller assembly, and more particularly to a controllable, adjustable pitch marine propeller assembly for commercial boats. The loads required to be propelled on commercial boats vary greatly. With each variance in load, it is extremely advantageous to be able to change the propeller pitch exacting amounts for optimum engine loading. Using fishing trawlers as an example, when the empty trawler goes out to sea, the optimum propeller pitch is completely different from that required for slow trolling, or for the return trip under load.

Mechanisms are currently provided for reversing the pitch of a propeller assembly. These ordinarily employ a hollow drive shaft to the propeller hub. A controlling pressure fluid actuates the propeller in reverse direction against the bias of a spring which normally holds the propeller in the forward direction. The hollow shaft principle is expensive, however, and does not enable a control unit to be attached to a conventional propeller mechanism without major rebuilding of the drive train. These known assemblies are difficult and expensive to repair. Further they do not provide accurate controllable pitch movement of the blades, but rather a two position forward-reverse action. Other controllable pitch propeller adjustment devices have also been devised. However, these involve complex mechanism with hollow shafting, and the like.

It is an object of this invention to provide a controllable pitch propeller which has a practically unlimited selection of propeller pitch angles in the forward direction to enable the propeller pitch to match the particular load conditions exactly, yet has a relatively simple structure. Another object of this invention is to provide such an assembly which can be attached to a conventional propeller drive shaft, enables controlled accurate blade pitch adjustment to suit light loads, heavy loads, high speeds, low speeds, or intermediate speeds, has double acting control, and yet has a relatively small number of interfitting parts. The mechanism does not utilize or require a hollow drive shaft, and enables initial installation and subsequent repairs to be relatively simple.

Another object of this invention is to provide a controlled pitch marine propeller assembly that will maintain its position at a set pitch angle even if the hydraulic unit should fail.

These and several other objects of this invention will become apparent upon studying the following specification in conjunction with the drawings, in which:

FIG. 1 is a side, elevational, fragmentary view of the stern of a boat showing the novel propeller assembly mounted to the drive shaft;

FIG. 2 is an enlarged, fragmentary, plan view of the novel propeller assembly;

FIG. 3 is a sectional, side elevational view of the apparatus taken on plane III-III of FIG. 2; and

FIG. 4 is a perspective view of the reciprocable, fluid actuated, two way, piston sleeve and integrally connected camming sleeve.

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Referring now specifically to the drawings, the novel propeller assembly 10 is shown mounted to the stern of a boat 12, such as a commercial fishing boat. The front end of the assembly is connected to a solid boat drive shaft 14. Its back end is mounted by a hollow support 16 attached to the boat. Hydraulic conduits lead through this hollow support 16 in a manner to be described.

The propeller assembly 10 includes the front propeller hub 18, a central housing section 20, and a fixed rear end cap 22. A plurality of propeller blades 24, usually three, project radially in an equally spaced manner from propeller hub 18. Each of the blades of the propeller has a propeller shaft, e.g., shaft 26, received in and retained by the housing assembly. The inner end of propeller shaft includes a peripheral outwardly, radially extending flange 28 received in a pair of annular L-shaped bearings fitted together to form a bearing 30 U-shaped in crosssectional configuration.

A cam follower pin 32 and its peripheral bearing sleeve 34 extend axially from the inner end of the propeller shaft, offset from the center line of the propeller shaft. The three cam follower pins of the three blades interfit in three respective diagonal slots 38a, 38b, and

380, formed at specific, like, acute angles, in the extended annular camming sleeve 40. This cylindrical sleeve is fitted axially within the housing of the propeller shaft assembly. The sleeve also includes three cutout portions 42 which interfit with three rearwardly extending guide portions 44 of the propeller hub to maintain a constant rotational relationship between the propeller hub and camming sleeve.

The integral opposite end of this camming sleeve comprises a fluid actuated axially shifting, two-way piston sleeve. It has a pair of radially extending annular flanges 46 and 48 spaced from each other by an intermediate periphetal recess 50. Annular seals such as O-rings 52 and 54 are inserted in receiving slots in these flanges 46 and 48 respectively. These seal the piston sleeve to the inner cylindrical wall 60 of central housing section 62. The axial rear end of the hollow piston sleeve is closed by the partition head 66 (FIG. 3).

The hollow piston sleeve has an interior fluid containing chamber 70. It receives the specially configurated sleeve guide and shaft cover nut 72. This nut is threadedly attached to the threaded rear end 74 of drive shaft 14. The end of the shaft is received by the propeller hub through a front opening, and is retained by a washer 77, a first nut 76, and the special locking nut 72. A set screw 78 secures nut 72 to the threaded end of the shaft.

The tapered end of the drive shaft is affixed in its rotational relationship to the propeller hub by a slot and key combination 80. A plurality of bolts 82 secure the propeller hub to the housing section 62 after the propeller shaft assembly and the drive shaft assembly are secured in the housing. Special nut 72 includes a front peripheral, outwardly extending flange 86 receiving an annular seal 88 to prevent fluid passage to the forward assembly. It also includes a rearwardly positioned radially extending diagonal peripheral flange 90 which maintains alignment of the piston sleeve as it is reciprocated. Reciprocation of the sleeve causes caming slots 38a, 38b, and 38c to be axially shifted also. This rotationally shifts the position of the camming pins to rotate the propeller shafts and blades due to the offset position of the cam follower pins.

The action of the camming sleeve and the piston sleeve is two-way, and can be controlled to give any particular intermediate position between the two extreme positions of the piston, one of which is shown in FIG. 3, and the other of which would be with end 66 adjacent flange 90 of nut '72.

The slots 38a, 38b, and 38c are purposely formed at a small acute angle of about 22 or less with respect to a iine along the surface of sleeve 40 and parallel to the axis of the sleeve. This causes the sleeve and blades to remain in fixed positions in case of fluid pressure failure, since water force on the propeller blades cannot rotate the blades.

The piston sleeve assembly is controlled by the entrance and exit of hydraulic fluid. This hydraulic fluid is introduced through the fixed or stationary rear end cap 22. This cap remains stationary due to its connection with support 16, while the other portions of the assembly rotate. The cap may actually vary widely in detail pro- Vided it includes mounting means, fluid passage means, and connection means to the rest of the assembly. A transition ring 94 is positioned between the particular cap shown and central housing 62. This ring is secured to housing 62 by bolts 96. The ring has a rearwardly extending, generally cylindrical, peripheral flange 100 which extends into the cap assembly. It also has a rearwardly extending axial plug 102 attached by nuts 104 to the center of ring 94. These two elements rotate with the ring and housing assembly.

The cap includes a generally cylindrical annular collar 106 between ring 100 and plug 102 secured by bolts 110. -A cover plate 112 is positioned at the rear end of the assembly to seal off plug 102 from the water. A pair of annular seals 114 is in constant rubbing contact with the cooperative, spring biased, rotating seal elements 116 to prevent water entry into the hydraulic fluid chamber 121.

The piston sleeve is reciprocated forwardly toward the propeller shaft from the position illustrated in FIG. 3 by hydraulic fluid flowing under pressure into rear chamber 120. Entry is made through passageway 122, annular chamber 124, passageway 126, through the center of nuts 104 into chamber 120.

Reciprocation of the sleeve in the opposite direction is achieved by entry of pressurized fluid into chamber 70, between nut 72 and inner face of head 66. This is achieved by transfer of fluid through passageway 130, annular chamber 121, passageway 132, passageway 134 in housing section 62, annular chamber 50, passageway 136 in the piston sleeve, annular chamber 138 around the periphery of nut 72, and passageway 140 through the nut into chamber 70.

In operation, it has been found that the mechanism is completely dependable, and actually enables accurate angular pitch adjustment of propeller shaft blades While remaining in the forward driving condition. It comprises an adjustable pitch propeller with hydraulic actuation in both directions. It has been found that with the small angle of the cam follower and slot combination, even if the hydraulic fluid system fails, the torque imparted to the blades by the water does not cause the blade pitch to shift. Rather, they remain constant and fixed at the previously set position. The unit can be attached to a conventional drive shaft without any machining or replacement of the drive shaft train. The propeller blades are actuated from the rear rather than from the front. Various other advantages will readily occur to those in the art upon studying the foregoing form of the invention. Also it is conceivable that certa n details of the structure may be modified o h t without departing from the concept presented. Therefore, the invention is to be limited only by the scope of the appended claims and the reasonable equivalents to those defined therein.

I claim:

1. An adjustable pitch marine propeller and drive shaft assembly enabling internal fluid actuated rotation of the propeller blades, but preventing external rotation thereof by water pressure on the blades, comprising: a rotatable propeller hub housing having an opening in its forward end to receive the drive shaft; a plurality of propeller blades radially around said housing, each having an end shaft received in said housing to revolve with said housing, each of said end shafts having a peripheral rotational bearing connection in said housing to allow rotation of the shafts on their axes; each of said end shafts having cam follower pin means on the inner end thereof, offset from the axis of said end shaft; a fluid cylinder, formed in the rear of said housing behindsaid end shafts and mounted to rotate with said housing; a hollow fluid actuator sleeve s-lidably mounted in said cylinder for fore and aft motion, having a cross partition, an inner chamber, and an annular outer peripheral recess, and including axially interfitting guide means interfltted with said housing to prevent rotation of said sleeve with respect to said housing while allowing axial movement thereof; a sealing and guide element mounted to the end of the drive shaft to rotate therewith, having seal means sealing the forward open end in engagement with the inner wall of said sleeve, and having an-annular outer peripheral recess; the integral forward end of said sleeve having like diagonal camming slots each at a small acute angle no greater than about 22 with respect to a line parallel to the axis of said sleeve, and receiving the respective offset pins on said propeller blade shafts; the interfit of said slots and offset pins having a binding action with reverse rotational force applied to said blades to prevent rotation thereof; a fixed non-rotatable rear end closure cap having a pair of fluid passage means to opposite sides of said sleeve to actuate it axially fore and aft and thereby controllably adjust the pitch of said propellers, one of said passage means extend-ing through said housing to said sleeve peripheral recess, including a passage from said sleeve peripheral recess through said sleeve to said guide element annular recess, and including a second passage from said guide element peripheral recess through said guide element to said sleeve inner chamber; and sliding seal means between said housing and said closure cap.

2. An adjustable pitch marine propeller and solid drive shaft assembly enabling internal fluid actuated rotation of the propeller blades, but preventing external rotation thereof by water pressure on the blades, comprising: a rotatable propeller hub housing having an opening in its forward end receiving the rear end of a solid drive shaft; a plurality of propeller blades radially around said housing, each having an inner end shaft received in said housing; each of said end shafts having a peripheral rotational bearing connection in said housing around the end shaft axis; each of said end shafts having a cam follower pin on the inner end thereof, offset from the axis of said end shaft; a fluid cylinder, formed in the rear of said housing behind said end shafts; a fluid actuator sleeve slid-ably mounted in said cylinder for fore and aft motion; said actuator sleeve having a hollow center forming an inner chamber, an open front end to said chamber, receiving the revolving end of the drive shaft, and an annular outer peripheral recess; said actuator sleeve also having a closed rear end portion, and including axial guide means'axially interfitted with said housing to prevent rotation of said sleeve with respect to said houslng but allow axial movement thereof; a sealing and guide nut mounted to the end of the drive shaft to rotate therewith; said nut having seal means sealing the forward open end of said sleeve, having portions in alignment engagement with the inner wall of said sleeve, and having an annular outer peripheral recess; the forward end of said sleeve having like diagonal camming slots each at a small acute angle and receiving the respective offset pins on said propeller blade shafts; the interfit of said slots and offset pins having a binding action with reverse rotational force applied to said blades to prevent rotation thereof; and a fixed rear end closure cap having a pair of fluid passage means to opposite sides of said rear end sleeve portion to actuate it fore and aft and thereby controllably rotate said propeller, one of said passage means extending through said housing to said sleeve peripheral recess, including a passage from said sleeve peripheral recess through said sleeve to said nut annular recess, and including a second passage from said nut peripheral recess through said nut to said sleeve inner chamber to form a constantly connecting fiuid system.

3. The assembly in claim 2 wherein said housing and closure cap are separated by a transition ring attached to References Cited by the Examiner UNITED STATES PATENTS 2,355,039 8/1944 Eves 170160.32 2,513,156 6/1950 Eaves 170-46021 2,93 1,443 4/1960 Pehrsson 170160.32 3,095,044 6/1963 Medlock 170160.47 X 3,153,454 10/1964 Gaubis 170-4601 X FOREIGN PATENTS 168,030 12/ 1954 Australia. 954,911 6/ 1949 France.

SAMUEL LEVINE, Primary Examiner.

said housing and retaining seal means in sliding contact 15 JULIUS E. WEST, Examiner.

with said closure cap. 

1. AN ADJUSTABLE PITCH MARINE PROPELLER AND DRIVE SHAFT ASSEMBLY ENABLING INTERNAL FLUID ACTUATED ROTATION OF THE PROPELLER BLADES, BUT PREVENTING EXTERNAL ROTATION THEREOF BY WATER PRESSURE ON THE BLADES, COMPRISING: A ROTATABLE PROPELLER HUB HOUSING HAVING AN OPENING IN ITS FORWARD END TO RECEIVE THE DRIVE SHAFT; A PLURALITY OF PROPELLER BLADES RADIALLY AROUND SAID HOUSING, EACH HAVING AN END SHAFT RECEIVED IN SAID HOUSING TO REVOLVE WITH SAID HOUSING, EACH OF SAID END SHAFTS HAVING A PERIPHERAL ROTATIONAL BEARING CONNECTION IN SAID HOUSING TO ALLOW ROTATION OF THE SHAFTS ON THEIR AXES; EACH OF SAID END SHAFTS HAVING CAM FOLLOWER PIN MEANS ON THE INNER END THEREOF, OFFSET FROM THE AXIS OF SAID END SHAFT; A FLUID CYLINDER, FORMED IN THE REAR OF SAID HOUSING BEHIND SAID END SHAFTS AND MOUNTED TO ROTATE WITH SAID HOUSING; A HOLLOW FLUID ACTUATOR SLEEVE SLIDABLY MOUNTED IN SAID CYLINDER FOR FORE AND AFT MOTION, HAVING A CROSS PARTITION, AN INNER CHAMBER, AND AN ANNULAR OUTER PERIPHERAL RECESS, AND INCLUDING AXIALLY INTERFITTING GUIDE MEANS INTERFITTED WITH SAID HOUSING TO PREVENT ROTATION OF SAID SLEEVE WITH RESPECT TO SAID HOUSING WHILE ALLOWING AXIAL MOVEMENT THEREOF; A SEALING AND GUIDE ELEMENT MOUNTED TO THE END OF THE DRIVE SHAFT TO ROTATE THEREWITH, HAVING SEAL MENS SEALING THE FORWARD 